EP0155527B1 - Device for cleaning semolina - Google Patents

Abstract

In the case of an apparatus for cleaning grits, which has a plurality of superimposed screen layers, which can be vibrated by means of at least one unbalance exciter and with an inlet or outlet for the product inlet or screen discharge arranged at one end, collecting means with adjustable setting flaps for the screenings, as well as an air circulation through the screen layers over an air distribution chamber in a suction collecting channel adjustable by means of adjusting flaps, it is provided that the apparatus is constructed as a stand with a stand head, a stand base and a vertical intermediate support connecting said two parts, the screen layers being constructed as a dust box and being vibratably supported in the vicinity of the stand base, the stand top being formed by the upper air distribution chamber.

Description

The invention relates to a device for cleaning semolina, which comprises: (a) a stand with a vertical central support; (b) a plurality of sieve layers arranged one above the other, which can be set into vibration by at least one unbalance exciter, each with an inlet or outlet arranged on one end side for the product inlet or sieve rejection, the sieve layers being designed as a cleaning box and being mounted on the stand so that they can vibrate; (c) collecting devices for the sieve diarrhea and (d) an air duct which can be adjusted by means of adjusting flaps through the sieve layers via an upper air distribution space into a suction collecting duct.

Such devices for cleaning semolina are special machines that are used almost exclusively in grain milling. They are used to sort out semolina and dun and occasionally maize semolina from the product fed to the machine. The main function of these machines is to sort the semolina of the largest possible granulation range (clean semolina, mixed products, light products, special products such as cooking semolina or similar, germs, etc.). The greatest possible yield of clean semolina should be achieved. Fluctuations in the incoming performance of the product should not have a negative impact on the quality of work, and the respective setting of the machine must not inadvertently change during the work process.

According to the principles of process engineering, it would be conceivable to obtain the individual components using a number of different separation systems, the main criteria being the following: heavy parts, sinking speed of the parts in the air flow and size of the good parts.

In other branches of process engineering z. B. fluidized beds with pulsating air, centrifugal classifiers, tarars, wind classifiers and other devices are used. However, it was found that such devices are not suitable for improving semolina cleaning machines. So far, the very specific requirements for the production of semolina could obviously only be met with the semolina cleaning machines that have been known for a long time. It was shown once again that, like in many other areas of technology, it is obviously particularly difficult to invent and implement practical new ideas in the field of semolina cleaning machines.

The well-known semolina cleaning machines have been developed so far in terms of both structure and function (and have also required certain framework conditions) that the experts could no longer expect a further noticeable improvement, at least with regard to the overall concept.

A device for cleaning semolina according to the type specified in the preamble of claim 1 is known from US Pat. No. 3,380,585 (SALETE) and from BÜHLER / BÜHLER-MIAG brochure no. MU 18206 D 8303 800 LB, "Semolina cleaning machine PUROSTAR / model MQRE "1983 known.

A semolina cleaning machine similar to the generic semolina cleaning machine is also known from AT-B 185 667 (GEBRÜDER BÜHLER).

The invention is based on the object of finding a semolina cleaning machine which runs particularly smoothly compared to known semolina cleaning machines, is lightweight and is more accessible.

According to the invention, this object is achieved in that in the generic semolina cleaning device mentioned at the outset, the vertical support merges into a foot at the bottom and the cleaning box is mounted so that it can vibrate downward at the foot of the stand and is supported there.

From CH-PS 631 092 (GEBRUDER BÜHLER AG) it is known per se to support sieve layers on a support so that they can vibrate downwards. However, this is a stand-alone plan sifter, not a semolina cleaning machine.

From AT-B 320 397 (GEBRUDER BÜHLER AG) a device and a method for separating bulk material mixtures according to the weight of the mixed material components, in particular a light grain reader, are known. Such a device also has a vibrating body. This is not used for sieving but for separating the products according to the weight. Sieves are therefore not available to separate the goods. The vibrating body in the known device rests on the surface, more precisely on the head of a base.

The solution according to the invention initially creates "free space" for easy access by the operator above the sieve boxes, which makes it particularly easy to keep the device itself and its surroundings clean. Since in the solution according to the invention the oscillatable support and mounting of the sieve layers designed as a cleaning box now takes place downward at the foot of the stand, a particularly quiet and vibration-free running of the entire device can be achieved, not least because the stand parts above the stand base for vibration compensation , ie can contribute to vibration damping as a result. In conventional machines, in which the support was provided in the form of suspensions on the housing for the machine, the housing had to absorb the vibrations which occurred, which resulted in a more uneven running. In contrast, in the solution according to the invention, much less reaction forces are exerted by the housing of the device To be included, which is why there is the possibility here for the first time to use a lightweight construction for the housing, which not only leads to a lower weight of the overall device, but also allows a more open construction of the same and thus easier accessibility. In the invention, the machine housing can be kept largely free of vibrations, since the vibrations of the cleaning box to be absorbed are derived downwards.

It is particularly advantageous if, in a semolina cleaning machine according to the invention, the stand has a stand head (11) and a vertical central support connecting it to the stand base, the upper air distribution space of the device being formed by the stand head itself or forming it. In the case of a semolina cleaning machine according to the invention designed as a double machine, the stand preferably has a central support at its front and rear ends.

It is also very advantageous in a device according to the invention if the cleaning box is supported by a spring system, as a result of which the entire oscillating structure is given two additional degrees of freedom for the oscillating movement. The spring system preferably has hollow rubber springs, steel springs or a rubber joint system, which makes it possible to connect the vibration exciter firmly to the cleaning box and still make the direction of action of the vibration exciter adjustable. In a further advantageous embodiment of the invention, the cleaning box is expediently designed as an oscillatable structure in the sense of a cantilever chair, whereby it can be supported, again on the two end sides, in an oscillating manner downward on the stand base. It is also advantageous in the case of a device according to the invention in the form of a double machine if a double conveyor trough vibrating in the same direction as the cleaning box is supported on the stand base so as to be capable of swinging independently of it. Advantageously, the cleaning box and the oscillating double conveyor trough are driven by a common unbalance exciter, whereby, again preferably, the cleaning box is firmly connected to the unbalance exciter and the direction of action of the unbalance exciter is adjustable. It can be advantageous to increase the swing stroke, the swinging double conveyor trough a lever joint from the vibrating unit to be driven by an end support from the cleaning box from the collecting devices can be set in motion by a drive lever and a support, the articulation points of the lever on the end support as are adjustable on the support of the fall arrester for setting the throwing distance.

The adjustability of the direction of force of the vibration exciter means that, depending on the choice of the direction of force with regard to the center of gravity of the vibrating unit, the vibrations at the beginning and at the end of the cleaning box can be adjusted in direction and intensity as required. When the fall arrester is supported by an oscillating lever system, as shown above, which can preferably be set in motion by the cleaning box by means of an adjustable drive lever, the oscillation deflection can be set independently of the oscillating movement of the cleaning box, although the same imbalance exciter is used to generate the vibrations.

Another preferred embodiment of the device according to the invention also consists in the fact that the center supports protrude in height above the cleaning box and merge symmetrically into a stand foot on both end sides, and that the space between the two stand feet is free of immovable, i.e. components that cannot be vibrated. This makes it possible to leave a lateral space for the air supply over the length of the entire device, even on the inside thereof.

Preferably, a resilient element is arranged between the stand and the cleaning box, as a result of which the reaction forces to the device, which result from the vibrating forces, can be absorbed well in the device, since the stand and stand head represent an effective countermeasure to the otherwise vibrating elements. As another preferred embodiment, the elastic element can be arranged between the stand foot and the central support of the stand. For certain applications, however, it is also advantageous if elastic elements are attached between the center support of the stand and the stand head. However, the center supports themselves can preferably also be designed as elastic elements, as a result of which particularly quiet and stable operation of the overall device can be achieved.

By supporting the vibrating masses downwards on the stand base, the vibrating forces are derived directly there, the stand being able to be designed for its main function for carrying the various elements. Because both the process of cleaning the semolina and the action of the necessary mechanical forces can be concentrated on their actual working zone, not only can a good quality of work be obtained and the product performance increase compared to conventional semolina cleaning machines, but also the service life of the entire device significantly increase compared to known machines. The vibrating forces can be kept completely away from the air guide elements, so that once the air guide has been set or the corresponding position of the air guide flaps can no longer adjust itself.

• Fig. 1 eine Längsansicht einer erfindungsgemäßen Vorrichtung;
• Fig. 2 den prinzipiellen Aufbau der nicht schwingenden Elemente einer erfindungsgemäßen Vorrichtung;
• Fig. 3 die Darstellung der Vorrichtung aus Fig. 2, ergänzt mit den schwingenden Elementen;
• Fig. 4 die Abstützung des Putzkastens bei einer erfindungsgemäßen Vorrichtung über ein Gummigelenksystem in prinzipieller Darstellung;
• Fig. 5 eine kombinierte Abstützung des Putzkastens bei einer erfindungsgemäßen Vorrichtung über Federn und einer Schwingförderrinne auf einem Hebelgelenk (in prinzipieller Darstellung), sowie
• Fig. 6 eine prinzipielle Darstellung der variierenden Kraftübertragungsmöglichkeiten vom Putzkasten auf die Schwingförderrinne bei einer erfindungsgemäßen Vorrichtung.

The invention is explained in more detail below in principle by way of example with reference to the drawing. Show it:

• 1 shows a longitudinal view of a device according to the invention;
• 2 shows the basic structure of the non-vibrating elements of a device according to the invention;
• FIG. 3 shows the device from FIG. 2, supplemented with the oscillating elements;
• Figure 4 shows the support of the cleaning box in a device according to the invention via a rubber joint system in a basic representation.
• Fig. 5 is a combined support of the cleaning box in a device according to the invention via springs and a vibrating conveyor trough on a lever joint (in a basic representation), and
• Fig. 6 is a schematic representation of the varying power transmission options from the cleaning box to the vibrating conveyor trough in a device according to the invention.

First, reference is made to FIG. 1, in which (as in the other figures) a so-called double machine is shown, which consists of two semolina cleaning machines that are completely separate in terms of working technology, as shown in FIG. 3. These two semolina cleaning machines are arranged on the left and right with respect to a central stand construction.

1 shows an inlet 1 at the top left for the product to be fed to the device and outlet 2 at the bottom right for the screen rejection. Furthermore, three screen layers arranged one above the other are provided, an inner collecting device 4 and an outer collecting device 5 being arranged under these (FIG. 3), in which the sieve diarrhea is collected. As a rule, each individual collecting device 4 or 5 has two processes 6 or 7. The sieve layers 3 are each combined to form a cleaning box 8 (FIG. 3), so that each cleaning box 8 is assigned two outlets 2 for the screen rejection and four outlets 6 and 7 for the screen diarrhea in accordance with the illustrated embodiment. Each cleaning box 8 is supported by an end support 12 (FIG. 1) via oscillating elements or hollow rubber springs 13 on a stand base 10 of a stand 9 so that it can vibrate. An unbalance exciter 14 is fixedly connected to the end support 12, the direction of impact (cf. arrow 15 in FIG. 1) can be adjusted by rotating the unbalance exciter 14 on a tubular cross-connection 16. Likewise, what is known can regulate the strength of the unbalance forces by appropriate adjustment of the unbalance weights 17. At the cross connection 16, two unbalance exciters 14 are attached and electrically connected so that they rotate in opposite directions. This eliminates their lateral unbalance components and there is a purely linear longitudinal vibration in the direction of arrow 15. A cover 18 is attached above the unbalance exciters 14, which is designed as part of the vibrating system for structural simplification.

The collecting device 4 is designed as a vibrating conveyor trough, which rests on both end sides on a support 19 mounted in rubber (FIG. 1). The oscillation drive of the collecting device 4 takes place via a lever 20 which connects the oscillating end support 12 to the support 19. Depending on the height of the point of application of the lever 20 on the support 19 (this height can be adjusted), the swing stroke of the collecting device 4 can thus be selected or adjusted independently of the swing stroke of the cleaning box 8. The stand 9 carries all non-vibrating components directly, the vibrating elements being mounted above the lower part of the stand. The stand 9 also has a vertical support 21 on each end side (FIG. 3), which merges with an extension into a foot construction at the bottom. According to the illustration in FIG. 3, the vertical support 21 extends a little beyond the uppermost sieve layer and carries a stand head 11, which essentially forms an upper air distribution space 22. This upper air distribution space 22 has an upwardly tapered shape and is divided over its length by bulkheads 23 into sixteen separate air guiding chambers 24. The bulkheads 23, as can be seen from FIG. 1, are brought close to the uppermost sieve layer, the distance being chosen so that it is somewhat larger than the greatest layer thickness of the material that ever occurs.

The upper inclined surfaces of the air distribution space 22 have transparent windows 25 over their entire length, so that the flow behavior of the material over the top sieve layer 3 can be controlled with an electric light source from the outside of the device.

2 shows the basic structure of the non-vibrating elements of the device (“stand construction”), two different exemplary embodiments being shown in this figure. The one embodiment shown is that an elastic or resilient element 30 is interposed between the stand base 10 and the vertical support 21. The other exemplary embodiment results from the arrangement of an elastic or resilient element 31 between the stand base 10 and the stand head 11. In the first case, the stand base 21 together with the stand head 11 represents a vibration damping mass for the non-oscillating parts. In the second example it forms the stand head 11 alone from the vibration damping mass. As an additional embodiment of this, the stand foot 21 could also be of a lightweight construction and itself embody the resilient element.

Another embodiment, which is particularly advantageous for certain applications, can be seen from FIG. 3. Between the cleaning box 8 and the drains 6 and 7, a base 32 which is supported on the stand 10 and which can swing is provided, which has a plurality of depressions 33 along its length, each of which has a longitudinal product flap or chute 34 (FIG. 3) on the inside or the outer collecting device 4 or 5 can be aligned so that the screen rejection, depending on the request, can be derived either into one or into the other collecting device below the sieve layers 3. The number of product longitudinal flaps 34 is preferably selected to be approximately the same size as the corresponding number of air guiding chambers 24.

From Fig. 3 it can also be seen that the working air flows over air intake gaps 35 provided on both sides. These measures bring various advantages: on the one hand, the guidance of the air flow is completely separate from the product discharge, which takes place below the floor 32, where there is no longer any air flow. On the other hand, the air flowing in from the side causes the product stream falling onto the bottom 32 to be deflected towards the center of the bottom, where the chute 34 is arranged, thus “concentrating” towards the inside. A still further advantage is also that the product flow is directed through the chute 34 to the interior of the vibrating collecting devices 4 and 5 and is derived via processes. In addition, the product flow brings a certain self-cleaning effect in the device: in the prior art, the changeover flaps are mounted directly on the collecting device 4 or 5, whereby a half of the collecting device in question is covered continuously, which leads to the formation of sealed-off dirt corners beneath it can, which in turn can not occur in the invention, since there is no cover there. Yet another noticeable advantage of the device according to the invention is that the sieve diarrhea can be divided very precisely into the desired fractions, because disturbing air flows in the longitudinal direction are virtually eliminated.

When the semolina cleaning machine shown is started up, the vibrator is switched on, so that the cleaning box 8, the bottom 32 and the collecting devices 4 and 5 carry out the preselected oscillating movement in the longitudinal direction of the device. Likewise, the entire device is placed in a slight negative pressure via a suction collection channel 27 or an aspiration associated therewith. Depending on the separation task, all slides and flaps are provisionally adjusted, after which the product can be fed into inlet 1. The product immediately falls on the top sieve layer 3. Due to the shaking movement which is imprinted on the material, as well as through the sieve layers which are deliberately inclined downwards from the inlet 1 to the outlet 2 and the air flow through the sieve layers 3, the product behaves like a liquid (fluidized ). The central task of the semolina cleaning machine lies in the actual sieving process. So the air flow must not be adjusted so much that the entire product layer could be lifted off the sieve layers. Rather, the air primarily serves the function of loosening up the product and distributing it evenly over the entire surface.

Depending on the task, it is required that the product should be fractionated into coarse, medium and fine size or into cooking size and medium size etc. In the second case, e.g. B. the first six chutes in the collecting device 4, the subsequent eleven chutes are directed into the collecting device 5. In this case, the two sieve passes are finished products that can be delivered to the corresponding storage cells or to the consumers. The screen rejects at the outlets are partially regrinded or crushed and then transferred to a second, appropriately set, semolina cleaning machine.

As can be seen from FIG. 1, two different processes 6 and 7 can be selected from each collecting device 4 or 5, so that four different fractions can be separated from each cleaning box 8.

In Fig. 4 the support of the vibrating unit is shown on a spring system 40, which is embodied by a rubber joint 43.

The unbalance exciter 14 can, as can be seen in FIG. 1, be rotated about the transverse axis 16, so that the direction of force 41 can optionally be set, as indicated by the arrow 41 '. If the direction of the force action passes through the center of gravity "S" of the vibrating unit (cf. FIG. 4), a uniform vibration of the entire stack of sieves is generally achieved. However, if the direction of force 41 does not run through the center of gravity "S", then - depending on the particular requirements - an actual vibration can be set in the area of the inlet 1 in accordance with the angle a and in the outlet 2 in accordance with the angle β.

5 and 6 represent another very particularly advantageous exemplary embodiment in principle: here the cleaning box 8 is mounted as an actual cantilever on a spring system 40 or a steel spring 42 so that it can vibrate. The unbalance vibrator 14, which is adjustable with respect to the direction of the force action, is fastened to the end support 12 and, by using two vibrators rotating in opposite directions, brings about an essentially purely linear oscillating movement in a manner analogous to that shown in FIGS. 4 and 1. The collecting device 4, 5 is independent of the cleaning box 8 a support 19 mounted to vibrate. The end support 12 is connected to the support 19 via a lever 20, so that the Vibrations of the unit which is supported so that it can oscillate transversely via the spring system 40 can be transmitted via the lever 20 to the collecting device 4, 5. The lever 20 can be attached to the support 19 at different heights x1, x2, ... x6 (cf. FIG. 6). This creates the possibility, starting from the drive of the unbalance vibrator 14 via a correspondingly selected and adjustable lever path, to trigger or force different lateral oscillation deflections of the collecting device 4, 5, thereby obtaining a surprisingly simple oscillating structure. The sieve stack performs a short-stroke oscillation for the "sieving" task, while the collecting device carries out a long-stroke oscillating throwing movement in accordance with the function of an oscillating conveyor trough, which is supported by the correct articulation of the lever 20 on the support 19. The work result of this combined cantilever lever arm has proven to be surprisingly good.

Claims (11)

1. Apparatus for the cleaning of grits which has:

a) a stand (9) with a vertical support (21),

b) several screening layers (3) which are arranged above one another and which can be made to vibrate by means of at least one unbalanced exciter (14), each with an inflow (1) and outflow (2) arranged on the respective end face and intended for the product inlet and screen ejection respectively, the screening layers (3) being designed as cleaning boxes (8) and being mounted vibrationally on the stand (9),

c) collecting devices (4, 5) for the throughs of the screenings, and

d) an air guide, adjustable by means of adjusting flaps, through the screening layers (3) into a suction-extraction collecting conduit (27) via an upper air distribution space (22), characterized in that

e) the vertical support (21) merges at the bottom in to a foot (10), and

f) the cleaning box (8) is mounted vibrationally downwards on the foot (10) of the stand (9) and is supported there.

2. Apparatus according to Claim 1, characterized in that the stand (9) has a stand

head (11) and a vertical middle support (21) connecting the stand head (11) to the stand foot (10), the upper air distribution space (22) forming the stand head (11).

3. Apparatus according to claim 2, in the form of a twin machine, characterized in that the stand (9) has a middle support (21) on each of the two end faces of the apparatus.

4. Apparatus according to one of claims 1 to 3, characterized in that the cleaning box (8) is supported via springs (40).

5. Apparatus according to claim 4, characterized in that the springs (40) are designed as hollow rubber springs (13), steel springs (42) or rubber joints (43).

6. Apparatus according to one of claims 1 to 5, characterized in that the cleaning box (8) is connected firmly to the unbalanced exciter (14), of which the direction of force effect (41) is adjustable.

7. Apparatus according to one of claims 1 to 6, characterized in that the collecting devices (4, 5) can be made to vibrate from the cleaning box (8), via an end support (12), by means of a drive lever (20) and a support (19), the points of articulation of the lever (20) being variable for the adjustment of the throw range.

8. Apparatus according to one of claims 3 to 7, characterized in that the middle supports (21) project beyond the cleaning box (8) in terms of height and at the bottom each merge symmetrically on both end faces into a stand foot (10), and in that the space between the two stand feet (10) is free of non-vibrationally mounted components.

9. Apparatus according to one of claims 3 to 8, characterized in that a double conveyor trough (4, 5) vibrating in the same direction as the cleaning box (8) is supported on the stand foot (10) independently of the cleaning box (8).

10. Apparatus according to one of claims 1 to 9, characterized in that the cleaning box (8) is designed as a freely vibrating structure.

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